This invention relates to high-capacity centrifuge rotors and, more particularly, to swinging-bucket centrifuge rotors that are capable of carrying large loads.
One type of centrifuge, known as a swinging-bucket centrifuge, pivotally supports swinging buckets or holders on a rotor. The buckets, in turn, support test tubes or other sample containers. Initially, when the centrifuge rotor is at rest, these swinging buckets hang downwardly. However, as the centrifuge rotor accelerates, the buckets tend to swing outwardly and upwardly under the influence of centrifugal force until they are almost horizontal, oriented radially outward. Following separation of the components in the sample containers, the rotor is decelerated allowing the buckets to fall back until they resume their former vertical hanging position.
One of the conventional designs used in such high-capacity rotors includes a rotor hub and an enclosed region having radial structural members which are fastened to the rotor hub. These members support not only the buckets but also an outer wind shield such that the wind friction on the swinging buckets is maintained within reasonable limits. A cover is usually provided to complete the rotor enclosure. Unfortunately, such radial members tend to limit the load space available within the centrifuge rotor.
Another problem is caused because the buckets are supported primarily by pins on the buckets themselves or on the rotor body. This means that portion of the buckets supporting the pins or pin sockets needs to be considerably strengthened and accordingly is bulky. This further tends to limit the capacity of the rotor.
It is known to use a band or ring at the periphery of the centrifuge to provide a bottom support for swinging buckets of this type. This has the particular advantage of reducing the bucket pin size required. Patents describing such swinging-bucket centrifuges using a peripheral band are German Patents Nos. 1,782,602, and 104,170; Swiss Patent No. 296,421; and British Patent No. 505,446. While all of these patents describe centrifuges using swinging-bucket rotors which have the above-noted advantages in reducing bucket pin size, unfortunately all tend to be somewhat restricted in the sense that their capacity is limited by the radial arms. In addition, the peripheral bands tend to become excessively heavy and in some cases to distort and bend, particularly under heavy loads. These factors necessitate unwieldy, larger centrifuge housings than is normally desireable to provide adequate operator protection.
Accordingly, it is an object of this invention to obviate many of the above-noted disadvantages of swinging-bucket centrifuges.
Another object of this invention is to provide an improved swinging-bucket centrifuge that is capable of handling relatively large volume loads and yet is of relatively light-weight construction.